A hydraulic unit comprising a switch valve of a generic type is known from DE 10 2009 011 983 A1. In the field of such so-called pressure-compensated switch valves, it is common knowledge to provide a groove in the housing part in which seal a sealing ring that serves to seal the valve body is inserted. Sealing rings of different types and shapes are known form the catalogue of the company of Kölbel Vertriebs GmbH, 93055 Regensburg published in the year 2010.